Clock and watch glossary

An analog watch represents time by position on a dial, whereas a digital watch is one in which the time is displayed as a series of digits, e.g. "11:28".

ALTIMETERAn altimeter is an active instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry.

AUTOMATIC WATCHAlso known as a "self-winding" watch, or for Rolex watches as "perpetual". These watches work by winding themselves up whilst being worn, so you don't need to wind them manually. The movement of the wrist turns an oscillating weight which keeps the mainspring wound up and the watch working. When not being worn most automatic watches, if fully charged, will run for about 2 days before stopping.

BEZELThis is the ring on the outside of the case that surrounds the dial of the watch. In some watches the bezel can be rotated, or may be set with crystals or diamonds to give the watch a more elegant look.

CARATThis is the measure of the purity of gold (and also platinum alloys), abbreviated as "CT". 24 carat gold is 100% pure, 18-carat gold is 75% gold, 12-carat gold is 50% gold, and so forth.

CASE BACKThe cover on the back of a watch which protects its insides whilst permitting access to the movement if required. It may be made of different materials ranging from plastic to 9ct gold, however stainless steel is most common. The case back usually flips off and is snapped back into place, although water resistant models frequently have a screw down back to make it harder for water to get into the watch.

CHRONOGRAPHA watch with a time and stopwatch functions. Click here for historical details.

CHRONOMETERA watch that has been subjected to rigorous testing by an official watch testing centre and has earned a certificate to validate its quality and accuracy.

CLASPThe fastener on the watch bracelet. There are different types depending on the style of bracelet and watch, with more heavy duty, sports and 9ct gold watches often having extra security features such as a fold over bar or push-button release.

COUNTDOWN TIMERA function which allows you to measure a preset period of time.

CROWNAlso known as the button. This is used to alter the time and date feature on most watches. It is also used to win-up the movement of mechanical watches. in some water resistant watches the crown can be screwed down for extra protection against water entering the watch.

DIALAlso known as the watch face. Some watches contain solar panels behind the dial.

DIGITAL (LCD)A watch, or display within a watch face, which uses a liquid-crystal display to display the time or other functions.

DUAL-DISPLAY and DUO TIMEA watch with both analogue and digital displays. Useful for watches with multi-functions, such as alarms and timers, and for keeping track of the time in two different time zones when travelling.

ECO-DRIVEThis is a type of solar-powered wrist watch, manufactured by Citizen Watch Co., Ltd. The watches use a Lithium ion battery that is charged by a solar cell behind the dial.

ELECTROPLATINGElectroplating is the process of using electrical current to coat an electrically conductive object with a very thin layer of metal. The main application of electroplating is to deposit a layer of a metal having some desired property (e.g., abrasion and wear resistance, corrosion protection, lubricity, improvement of aesthetic qualities, etc.) onto a surface lacking that property.

GLASSThe protective cover over the dial of the watch. The glass may be made of different materials, with the most common being acrylic crystal - inexpensive and light scratches can be buffed out. Alternatives include: mineral crystal - a hardened glass which is treated to be more resistant to scratches, and sapphire crystal - the most expensive and durable. Sapphire has a hardness second only to diamond, so it is highly resistant to scratches. It is 3 X harder than mineral crystal and 20 X harder than acrylic crystal.

GOLDA precious metal which is most commonly used in its 9 carat and 18 carat forms.

HALLMARKThis is the authorised stamp from an assay office which is found on items of gold, silver and platinum. The hallmark indicates the authenticity and standard of the precious metal and is awarded after independent tests by the official assay offices at London, Birmingham, Sheffield or Edinburgh.

KINETICA watch movement, created by Seiko, which utilises hand movements charge up a rechargeable cell within the watch. These watches are clever because there is an auto-relay 'sleep mode' that permits reversion to normal battery usage if the watch is stationary for more than a certain period.

LUGSThe projections at either side of the watch case which help hold the strap or bracelet in place through the use of a spring bar.

LUMINOUSA self-illuminating coating sometimes found on watch dials and hands which make them visible in the dark.

MECHANICALA traditional movement which is powered by a mainspring which is wound up by hand using the crown. As the mainspring slowly unwinds it drives the intricate workings of the watch movement.

MINERALCRYSTALGLASSA hardened glass which is treated to be more resistant to scratches.

MOONPHASEA feature on some watches which allows you to keep track of the moon's phases.

MOTHER OF PEARLTaken from the inside of the shell of a freshwater mollusc, this is an attractive and iridescent material which is sometimes used on the dial of a watch. Iridescent materials change hue according to the angle from which the surface is viewed.

MOVEMENTThe inner workings of a watch. There are several different types of watch movement, including: mechanical, automatic, quartz, kinetic, and eco-drive.

NICKELCONTENTNickel used to be used in the electroplating process to help the coating adhere to what was being plated. However, as more and more people have become allergic to nickel the EU introduced guidelines restricting the amount of nickel in jewellery and watches to minimal safe levels. Now copper is used to aid the electroplating process and all watches that we sell are within the EU guidelines and can be described as NICKEL SAFE. No watches can be described as nickel free though.

PERPETUAL CALENDARA feature of some watches where the date is always correct as it automatically adjusts to take account of the different lengths of the months and leap years.

QUARTZQuartz oscillates at an exact known frequency when an electric current is passed through it. While in Grandfather clocks, the "oscillator" is the pendulum, in quartz watches the quartz acts as a miniature pendulum. When driven by an electric current from a battery, quartz is known to oscillate at a 32,768 times per second. Quartz then passes the electric current back to an integrated circuit at this rate. Impulses are transmitted to a mechanical motor which drives the hands of the watch.

ROTATING BEZELA bezel that can be turned round, usually anti-clockwise. They can be used for different reasons on different watches.

SAPPHIRE CRYSTAL GLASSSapphire has a hardness second only to diamond, so it is highly resistant to scratches. It is three times harder than mineral crystal and twenty times harder than acrylic crystal. It is a material commonly used in both the front and back casings of wristwatches, especially in skeleton watches, and in watches designed to be highly resistant to damage such as those used by divers or by the military.

SCREW-DOWN CROWNSome water resistant watches have a crown that can be screwed-down onto the watch case itself. This adds extra protection from water entering the case.

SEALSynthetic gaskets which are used to provide a water-tight barrier, or seal, at different points in the watch, most commonly between the watch back and case. SPRING BARA telescopic metal pin used to attach the strap or bracelet onto the watch case between the lugs.

STAINLESS STEELA dense, highly durable and rust-resistant metal often used for watch cases and bracelets. Its natural colour and hardiness means that it only needs to be electroplated if a gold colour is required. It can be given either a polished or matt finish, or a combination of the two for a more decorative finish.

STERLING SILVERA precious metal used in some watches and watch bracelets. It is assayed and hallmarked to confirm that it contains at least 92.5% pure silver.

TACHYMETER / TACHOMETERA function of a watch which can measure the speed at which the wearer is travelling.

TITANIUMA very lightweight yet strong hard-wearing metal of a greyish appearance. It is much stronger than stainless steel when alloyed but also much lighter, making it perfect for watch cases and bracelets. Titanium was first discovered in England by William Gregor in 1791. It is highly resistant to corrosion, and is non-toxic. Titanium may also be used in spectacle frames.

WATER RESISTANTThis is the measure of how suitable a watch is for various water activities. An appropriate measure of water resistance is in ATMOSPHERES (ATM), where 10 ATM is equivalent to 10 metres of water pressure (or 1 BAR). As a rough guide as to what can generally be done at the different levels of water resistance:

Up to 30 metres (3ATM or 3bar) - just splashproof. 50 metres (5ATM or 5bar) - suitable for swimming in shallow water. 100 metres (10ATM or 10bar) - suitable for swimming or snorkelling. 200 metres (20ATM or 20bar) - suitable for skin diving. If you want to go scuba diving you will need to purchase a watch especially designed for diving.

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